if it's recent, that's a relief. i know it's hard to think of 'relief' when your kid is suffering, but it doesn't sound so much like a personality thing as a phase thing. does that make sense? not something she's struggled with her whole life, so she just needs to get over this hump.
i think most kids hit a wall where social status suddenly looms in importance, out of proportion. so a kid who may have formerly been confident and cheerful suddenly feels on the outside.
it's a tough place for a mom to be, but i'd caution against being too vigorous and pro-active about 'fixing' this. you want her to feel not only socially comfortable, but empowered, so want to avoid making her feel as if her friendships can be manufactured.
the smartest (and easiest) thing to do is to find other outliers and form unlikely friendships from the others who don't necessarily fit in right now. often these little groups become the new in-crowd. and it's a big and lovely life lesson to experience how being nice to someone who is marginalized can blossom into something more.
and even if it doesn't, being nice to someone who's marginalized is a good thing to do.
never hurts to do a little role-playing. you be her, and tell her to be the girl who concerns her the most, and have her respond in a fashion she thinks would be the most hurtful. then you give her a variety of thoughtful responses. like if she thinks the queen bee would say 'what are you doing here? you're not one of us' her response could be a cheerful 'you're right! i totally over-estimated you!' or a more low-key 'i wrongly assumed you were cool people. i apologize for interrupting you' (or whatever a 9 year old version of that would sound like<G>.)
i mean, it's not likely that they'll throw rocks at her or call her names, right?
you could have a quiet word with the school, but don't go overboard in having adults intervene, it could backfire. just keep quietly and confidently inspiring her WITH confidence. if you trust her to get past this, she'll pick up on your backstory and carry it forward with her.
ETA what i would NOT do is homeschool over it, homeschool advocate though i am. i disagree with new granny that self-esteem is (or should) be so fragile that a child needs to be 'protected.' obviously a kid who is being hammered, or abused, or ripped down needs protection, but most normal kids going through most normal childhood experiences need to be empowered, not bubble-wrapped.
homeschool should be about the best opportunity for academic achievement and a family philosophy, not someplace to hide.
khairete
S.